1. Field of the Invention
The present invention relates to contacts on an integrated circuit chip, and particularly to improvement for contacts on an integrated circuit chip, with which each of the contacts at the bearing part thereof can be disposed at the same level during the contacts being inset and flattened, so that deformation resulting from being pressed can be avoided to facilitate the adhesion of the tin solder ball.
2. Description of Related Art
Presently, the base of an integrated circuit chip is associated with the main board by way of contacts on the base are arranged a tin solder ball respectively and the base being possible to be welded to the main board directly in the process of passing tin solder furnace instead of the conventional way that the contacts are inserted into the base first and then are welded to the main board.
A type of contact available in the market provides an elongated hole with a shape of bended clip. The elongated hole is used for being inserted with connecting pins on the integrated circuit chip and the tin solder ball is disposed at an open end of the contact.
However, it is hard for the preceding tin solder ball to join with the contact and it is easy for the tin solder ball to be disposed at a level different from that of the neighboring tin solder balls. Besides, it is easy for the tin solder ball to fall down during the process of tin solder ball being embedded. Moreover, there is no locating device between the base and the contacts so that the contacts are not possible to be located at the base firmly and it results in the contacts being disposed at inconsistent levels on the base after being inserted into contact grooves. Hence, the conventional contacts do not allow the base on the integrated circuit chip to contact with the main board correctly.
U.S. Pat. No. 6,267,615 discloses a contact, which includes a main part, wing parts, elastic arms, a clamp part and a bearing part. The wing parts are bowed and provided at both lateral sides of the main part with a respective end thereof extending upward the elastic arms with a space between the elastic arms being getting smaller to the top thereof. The clamp part is disposed at the upper edge of the contact with asymmetric guide planes.
Because the asymmetric guide planes of the clamp part on the contact disclosed in the U.S. Pat. No. 6,267,615 cause the connecting pins on the integrated circuit chip moving along non-smoothly displacement lines, it is very likely for the connecting pins to become bent during the process of contacting with the base thereof and a phenomenon of improper contact will occur. Further, the contact being located at the base totally depends on frictional interference between the contact and the base instead of a locating device so that inconsistent inserted positions can occur in case of all the same type contacts being inserted to the base. Under this circumstances, it is hard for the contact to join with a tin solder ball and an inconsistent level will occur in case of comparing to tin solder balls in neighboring contacts. Moreover, there is no support for the bearing part of the contact itself so that the bearing part is easy to become bent as the contact is inserted into the contact groove. Hence, the bearing part of each contact is not possible to be fixed at the same level and consistent positions for the contacts are not possible to obtain such that the tin solder balls are not possible to join with the contacts. Furthermore, because a great deal of contacts are inserted into the base SO that it is easy for the base to become deformed under the condition of the contacts interfering each other and squeezed each other.
A primary object of the present invention is to provide contacts on an integrated circuit chip, with which the contacts at the bearing parts thereof can be disposed at the same level during the contacts being inset with a base of the integrated circuit chip and being flattened, so that deformation resulting from being pressed can be avoided so as to facilitate the adhesion of the tin solder balls.